package datastructurs.huffuman;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class HuffmanTree {
    public static void main(String[] args) {
        int arr[] = {13,45,3,4,5,6,7,8,1,58};
        Node root = createHuffmanTree(arr);
        preOrder(root);
    }

    public static void preOrder(Node root){
        if(root!=null){
            root.preOrder();
        }else {
            System.out.println("该哈夫曼树为空");
        }
    }
    //创建哈夫曼数
    public static Node createHuffmanTree(int[] arr){
        List<Node> nodes = new ArrayList<>();
        for(int value:arr){
            nodes.add(new Node(value));
        }
        while(nodes.size()>1){
            Collections.sort(nodes);
            Node leftNode = nodes.get(0);
            Node rightNode = nodes.get(1);

            Node parent = new Node(leftNode.value+rightNode.value);
            parent.left = leftNode;
            parent.right = rightNode;

            nodes.remove(leftNode);
            nodes.remove(rightNode);

            nodes.add(parent);
        }
        return nodes.get(0);

    }
}

class Node implements Comparable<Node>{
    int value;
    Node left;
    Node right;

    //前序遍历
    public void preOrder(){
        System.out.println(this);
        if(this.left!=null){
            this.left.preOrder();
        }
        if(this.right!=null){
            this.right.preOrder();
        }
    }
    public Node(int value) {
        this.value = value;
    }

    @Override
    public String toString() {
        return "Node{" +
                "value=" + value +
                '}';
    }

    @Override
    public int compareTo(Node o) {
        return this.value-o.value;
    }
}